How to counter Syndra
Let us take a look on how to beat Syndra. We will look at champions who are strong against Syndra and who are weak against Syndra. Use win rate, gold difference and creep score difference at minute 10 to find the best 
Mid champion who counters Syndra. You can already win in champion select with the right counters for Syndra. If you want to know how to counter Syndra then you need to take into account the best picks vs Syndra and the worst picks vs Syndra. This Syndra counter data is based on matches played by Pros on patch 14.9 and previous ones. It is important to see whether Pros counter picked Syndra or whether they played as Syndra.
Champions used by Pros to counter pick Syndra
Looking at the matches from Pros (see table Pros counter picked Syndra) we can see that they picked 
Azir most often to counter pick Syndra. The matchup Azir vs Syndra occured 17 times. Syndra has 8 wins and 9 losses in this matchup. Learn how to counter pick Azir to get another perspective on the data.
Lane outcome for Syndra
When looking at Syndra counters you will notice that win rates alone are not conclusional. Therefore we provide an overview (see table Lane Outcome) where you can see the lane outcome of Pros who played Syndra. The lane outcome of Syndra consists of three outcomes: Win, Loss or Draw. Let's take a look of Syndra lane and match outcome for specific matchups. Considering the lane outcome and the match outcome of a specific matchup, might enable you to find the right counter for Syndra.
Conclusion
Analyze the available data and learn how to beat Syndra. To master Syndra take also a look on Syndra builds and runes for Syndra. Good luck, Summoner!